The present invention generally relates to the field of tube coupling devices, and more particularly, to a device for releasably attaching an end of a tube or catheter to a port of a fluid transport device.
Flexible tubes or catheters are often used with transport devices for fluid delivery systems. For example, numerous surgical and non-surgical treatment procedures require that a catheter be placed in fluid communication with a patient's vascular system. A number of devices for this purpose are known. Both implantable treatment reservoirs, such as disclosed in U.S. Pat. No. 4,673,394, and traditional cannula devices, afford access to a patient's vascular system, using catheters attached to those devices.
Such devices may also be used for blood transfer, for example, in hemodialysis. U.S. patent application Ser. No. 354,614, assigned to the same assignee as the present application, discloses devices that are particularly adapted for this purpose. Flexible tubes are also used extra-corporeally to establish a desired fluid transport system. In the latter application, the tubes are often fit with connectors to permit flexibility in the assembly of a desired system from standardized components.
With regard to implantable vascular access devices of the prior art, catheters are typically permanently affixed to the implantable device prior to implantation. It is also known to use an implantable device which is adapted for attachment of a catheter to a chambered extension (i.e., a fluid exit or inlet port) of that device during the implantation procedure, but after the device is positioned within the patient. Typically, such catheters are adapted to be slidingly placed over a tubular port, and to be frictionally held in place.
In view of the nature of the procedures by which implantable treatment devices are surgically implanted in patients, it is necessary that the connection between a catheter and the implantable device be easily accomplished. This enables a surgeon to concentrate on the proper placement of the implantable device. Nevertheless, the friction fit and placement of the catheter has proven to require some degree of skill and patience during implantation.
Known connectors, such as, for example, a mere collar circumscribing the catheter and which fits over a tubular port projecting from the implantable device, often do not afford secure attachment. If the inner diameter of the collar does not properly correspond to the outer diameter of the catheter, either the collar will not fit over the catheter, or the collar will not generate a sufficient compressive force to secure the catheter to the port. With known assemblies, therefore, it is necessary to keep on hand a variety of connectors so that an appropriate connector can be selected and used which will specifically accommodate the particular catheter being connected.
U.S. Pat. No. 4,673,394 discloses a particularly effective arrangement for attaching a catheter to an implanted access device. That arrangement includes a twist-lockable (bayonet-type) coupler in which a pair of bayonet pins extend in opposite directions from the generally cylindrical outer surface of the coupler. The pins, together with the geometry of the coupler, may be slidingly positioned over the tubular port of the implant with a particular angular orientation, and then twisted so that the pins are captively held in place by portions of the implant which define a void region used to capture the pins.
Of course, care must be taken such that the action of twisting the bayonet-type coupler to lock the catheter to the implant does not cause the catheter to be damaged. Even with such care, torquing of the catheter should be avoided, since a twisted catheter may become partially blocked to fluid flow, or worse yet, especially in multiple lumen catheters, may become entirely blocked to fluid flow.
It is therefore an object of the present invention to provide an improved connector for securely attaching a flexible tube, such as a catheter, to a chambered extension, such as a tubular fluid exit or inlet port, of a fluid transfer assembly, such as an implantable fluid delivery device.
It is another object of the invention to provide a catheter-to-device connector which is easily installed, provides a frictional lock between the catheter and device and enables twist-lockable action between the connector and device without substantially twisting the catheter.
It is another object of this invention to provide a catheter-to-device connector which is constructed so that in the process of attaching a catheter to the device an annular thickness portion of the catheter wall is formed at the contact surface of the device to create an improved seal.
It is yet another object of this invention to provide a catheter to device connector which can provide in the attached position a positive lock retaining the connector in the attached position.
It is yet another object of the invention to provide a compression sleeve for use with a catheter connector to provide greater compressive interaction between the catheter and a fluid exit or inlet port of an implantable device.